2.2.2-Cryptand

[2.2.2]Cryptand

Skeletal formula of 2.2.2-cryptand
Names
Preferred IUPAC name 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane
Other names Cryptating agent 222[1]
Identifiers
CAS Number	23978-09-8^Y
3D model (JSmol)	Interactive image
Abbreviations	Crypt-222
Beilstein Reference	620282
ChemSpider	65637^Y
ECHA InfoCard	100.041.770
EC Number	245-962-4
MeSH	Cryptating+agent+222
PubChem CID	72801
RTECS number	MP4750000
UNII	18V22YHN6G^Y
CompTox Dashboard (EPA)	DTXSID00178697
InChI InChI=1S/C18H36N2O6/c1-7-21-13-14-24-10-4-20-5-11-25-17-15-22-8-2-19(1)3-9-23-16-18-26-12-6-20/h1-18H2^Y Key: AUFVJZSDSXXFOI-UHFFFAOYSA-N^Y InChI=1/C18H36N2O6/c1-7-21-13-14-24-10-4-20-5-11-25-17-15-22-8-2-19(1)3-9-23-16-18-26-12-6-20/h1-18H2 Key: AUFVJZSDSXXFOI-UHFFFAOYAX
SMILES C1COCCN2CCOCCOCCN(CCO1)CCOCCOCC2
Properties
Chemical formula	C 18N 2H 36O 6
Molar mass	376.4882 g mol^−1
Melting point	68 to 71 °C (154 to 160 °F; 341 to 344 K)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P305+P351+P338
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is ^YN ?) Infobox references

[2.2.2]Cryptand is the organic compound with the formula N(CH₂CH₂OCH₂CH₂OCH₂CH₂)₃N. This bicyclic molecule is the most studied member of the cryptand family of chelating agents.[2] It is a white solid. Many analogous compounds are known. Their high affinity for alkali metal cations illustrates the advantages of "preorganization", a concept within the area of supramolecular chemistry.

For the design and synthesis of [2.2.2]cryptand,[3] Jean-Marie Lehn shared the Nobel Prize in Chemistry. The compound was originally prepared starting with the diacylation of the diamine-diether:[4]

[CH₂OCH₂CH₂NH₂]₂ + [CH₂OCH₂COCl]₂ → [CH₂OCH₂CH₂NHC(O)CH₂]₂ + 2 HCl

The resulting macrocyclic diamide is reduced by lithium aluminium hydride. The resulting macrocyclic diamine tetraether reacts with a second equivalent of [CH₂OCH₂COCl]₂ to produce the macrobicyclic diamide. This di(tertiary)amide is reduced to the diamine by diborane.

[2.2.2]Cryptand binds K^+ as an octadentate N₂O₆ ligand. The resulting cation K([2.2.2]cryptand)^+ is lipophilic.

Structure of [2.2.2]cryptand encapsulating a potassium cation (purple) as determined by X-ray crystallography[5]

References

1. In the Nomenclature of Inorganic Chemistry (2005), IUPAC recommends the abbreviation crypt-222.
2. Kang, Sung Ok; Llinares, José M.; Day, Victor W.; Bowman-James, Kristin (2010). "Cryptand-like anion receptors". Chemical Society Reviews. 39 (10): 3980–4003. doi:10.1039/C0CS00083C. PMID 20820597.
3. Dietrich, B.; Lehn, J.M.; Sauvage, J.P. (1969). "Les Cryptates". Tetrahedron Letters. 10 (34): 2889–2892. doi:10.1016/S0040-4039(01)88300-3.
4. Dietrich, B.; Lehn, J.M.; Sauvage, J.P. (1969). "Diaza-polyoxa-macrocycles et macrobicycles". Tetrahedron Letters. 10 (34): 2885–2888. doi:10.1016/S0040-4039(01)88299-X.
5. Alberto, R.; Ortner, K.; Wheatley, N.; Schibli, R.; Schubiger, A. P. (2001). "Synthesis and properties of boranocarbonate: a convenient in situ CO source for the aqueous preparation of [^99mTc(OH₂)₃(CO)₃]^+". J. Am. Chem. Soc. 121 (13): 3135–3136. doi:10.1021/ja003932b. PMID 11457025.